Preparation method and device of coal gangue sandblasting abrasive and coal gangue sandblasting abrasive

Abstract

This disclosure relates to the field of waste resource utilization technology, and in particular to a method and apparatus for preparing coal gangue blasting abrasive, as well as the coal gangue blasting abrasive itself. The method includes: feeding coal gangue tailings to a hydrocyclone for coal slime removal to obtain coarse-grained coal gangue; centrifuging the coarse-grained coal gangue to obtain dehydrated coal gangue; and feeding the dehydrated coal gangue into a hot air drying system for drying to obtain dried coal gangue blasting abrasive. Through targeted coal slime removal, the amount of dust generated during the blasting process of the coal gangue blasting abrasive can be reduced, improving the environment; processing coal gangue tailings into coal gangue blasting abrasive results in extremely low raw material costs, and the entire process allows for wastewater recycling without secondary pollution.

Description

Technical Field

[0001] This disclosure relates to the field of waste resource utilization technology, and in particular to a method and apparatus for preparing coal gangue blasting abrasive, as well as the coal gangue blasting abrasive itself. Background Technology

[0002] In the coal washing process, spiral separators are widely used for separating fine coal particles, and the tailings produced are mainly fine coal gangue. These tailings have low utilization value and are usually stockpiled or landfilled, which not only occupies land but also poses risks of spontaneous combustion and environmental pollution. There is a lack of green treatment and rational utilization of coal gangue. Summary of the Invention

[0003] In view of the above problems, this disclosure is made to provide a method and apparatus for preparing coal gangue blasting abrasive, as well as the coal gangue blasting abrasive.

[0004] According to one aspect of this disclosure, a method for preparing a coal gangue blasting abrasive is provided, comprising: Coal gangue tailings are sent to a hydrocyclone for coal slime removal to obtain coarse-grained coal gangue. The coarse-particle coal gangue is centrifuged and dehydrated to obtain dehydrated coal gangue. The dehydrated coal gangue is fed into a hot air drying system for drying to obtain dry coal gangue blasting abrasive.

[0005] The beneficial effects of this solution are as follows: Targeted coal slime removal technology reduces dust generation during coal gangue blasting, improving the environment; processing coal gangue tailings into blasting abrasive results in extremely low raw material costs, and the entire process allows for wastewater recycling without secondary pollution; the coal slime removal and centrifugal dehydration processes effectively reduce the soluble salt content in the coal gangue, helping to lower the risk of rust reappearance on metal surfaces after blasting. The two-stage dehydration mode of "centrifugal dehydration + hot air drying" reduces the load on the hot air drying system, lowers costs, and produces coal gangue blasting abrasive with uniform particle size, high hardness, and excellent cutting ability and rust removal efficiency.

[0006] Furthermore, according to one aspect of the preparation method of this disclosure, the dehydrated coal gangue has a moisture content of 10% to 15%.

[0007] Furthermore, according to one aspect of the preparation method of this disclosure, the drying temperature is 80°C to 150°C.

[0008] Furthermore, according to one aspect of the preparation method of this disclosure, the moisture content of the coal gangue blasting abrasive is less than or equal to 0.5%.

[0009] Furthermore, according to one aspect of the preparation method of this disclosure, the particle size of the coal gangue blasting abrasive is 0.1~2mm, and the Mohs hardness is greater than or equal to 5.

[0010] Furthermore, according to one aspect of the preparation method of this disclosure, the underflow inlet of the hydrocyclone is equipped with a high-frequency vibrating screen with a spraying device for removing fine coal slime from the surface of the coal gangue tailings, wherein the particle size of the fine coal slime is less than or equal to 0.1 mm.

[0011] Furthermore, according to one aspect of the preparation method of this disclosure, the centrifugal dewatering treatment is completed in a centrifugal dewatering machine, which is a horizontal scraper centrifuge. The filtrate produced by the centrifugal dewatering machine can be recycled into the filtrate system of a coal preparation plant.

[0012] Furthermore, according to one aspect of the preparation method of this disclosure, the heat source of the hot air drying system is waste heat from a boiler or steam from a coal gangue power plant.

[0013] According to another aspect of this disclosure, a coal gangue blasting abrasive is provided, which is prepared by the above-described preparation method.

[0014] According to another aspect of this disclosure, an apparatus for preparing coal gangue blasting abrasive is provided, which applies the above-described preparation method.

[0015] It should be understood that both the foregoing general description and the following detailed description are exemplary and intended to provide further illustration of the claimed technology. Attached Figure Description

[0016] The above and other objects, features, and advantages of this disclosure will become more apparent from the more detailed description of the embodiments thereof in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this disclosure and form part of the specification. They are used together with the embodiments of this disclosure to explain the disclosure and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0017] Figure 1 This is a flowchart illustrating a method for preparing coal gangue blasting abrasive according to an embodiment of the present disclosure.

[0018] Figure 2 This is a flowchart illustrating another preparation method according to an embodiment of the present disclosure. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this disclosure more apparent, exemplary embodiments according to this disclosure will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this disclosure, and not all embodiments of this disclosure. It should be understood that this disclosure is not limited to the exemplary embodiments described herein.

[0020] In the coal washing process, spiral separators are widely used for separating fine coal particles, and the tailings produced are mainly coal gangue. These coal gangue tailings have fine particle size, high moisture content, and low utilization value. They are usually stockpiled or landfilled, which not only occupies land but also poses risks of spontaneous combustion and environmental pollution.

[0021] To utilize coal gangue tailings, it can be applied to sandblasting for rust removal. Sandblasting is a widely used surface treatment technology, with abrasives as its core consumable. Traditional quartz sand abrasives have been restricted due to their association with silicosis; industrial byproduct abrasives such as copper slag pose compositional fluctuations and potential pollution risks; while high-end abrasives such as brown fused alumina are prohibitively expensive. Therefore, developing a low-cost, high-performance, and environmentally friendly alternative abrasive is of great significance.

[0022] Coal gangue's main components are SiO2 and Al2O3, with a Mohs hardness typically between 4 and 7. Quartz-rich coal gangue, in particular, exhibits high hardness and sharp edges. Furthermore, the particle size of coal gangue tailings is less than 2mm, theoretically making it ideal as abrasive for sandblasting. However, directly using coal gangue tailings for sandblasting presents the following problems: (1) High content of fine mud: There is a large amount of fine mud (particle size <0.1mm) in coal gangue tailings. These fine muds will generate huge dust when sandblasting, polluting the environment, endangering health, and affecting cleaning efficiency.

[0023] (2) High moisture content: Wet separation results in high moisture content of coal gangue tailings, which cannot be directly used in sandblasting equipment, while conventional drying methods are energy-intensive and costly.

[0024] The above description, with reference to the accompanying drawings, describes a method and apparatus for preparing a coal gangue blasting abrasive according to an embodiment of the present disclosure. Through a specific process of "water spraying desliming - centrifugal dewatering - hot air drying", harmful fine mud and moisture in coal gangue tailings are effectively removed, resulting in a high-quality blasting abrasive that is low-cost, high-efficiency, and low-pollution.

[0025] To facilitate understanding of this embodiment, a method for preparing a coal gangue blasting abrasive disclosed in this disclosure will first be described in detail, such as... Figure 1 The flowchart shown is a method for preparing coal gangue blasting abrasive provided in this embodiment of the present disclosure, including: (1) Coal slime removal.

[0026] Specifically, the coal gangue tailings discharged from the spiral separator are transported to the hydrocyclone classifier. The underflow flows by gravity into the high-frequency vibrating fine screen for classification. The water spray device above the fine screen washes the tailings, peels off the fine coal slime (particle size ≤ 0.1 mm) on the surface and discharges it, resulting in deslimed coarse coal gangue.

[0027] The hydrocyclone for classification has a diameter of Φ250 mm and a feed pressure of 0.12 MPa. Hydraulic classification is achieved by flushing with jet-pressure water followed by classification using a hydrocyclone or dewatering screen. The separated wastewater containing fine coal slime enters a thickening tank for sedimentation, and the supernatant is recycled for the coal slime removal process.

[0028] (2) Centrifugal dehydration.

[0029] Coarse coal gangue is fed into a centrifugal dewatering machine, where centrifugal force removes a large amount of water from the coarse coal gangue, reducing its moisture content to 10%~15%, thus obtaining dewatered coal gangue.

[0030] Among them, the centrifugal dewatering machine is a horizontal scraper centrifuge, and the filtrate can be recycled into the filtrate system of the coal preparation plant.

[0031] (3) Hot air drying.

[0032] Specifically, dehydrated coal gangue is fed into a hot air drying system and dried at a temperature of 80℃~150℃. By controlling the hot air flow rate and the material residence time, the final moisture content is reduced to below 0.5%, resulting in dry and loose coal gangue blasting abrasive.

[0033] The hot air drying system is a belt dryer, with its heat source coming from boiler waste heat or steam from a coal gangue power plant. The coal gangue blasting abrasive has a particle size of 0.1~2mm, a moisture content of ≤0.5%, and a Mohs hardness of not less than 5.

[0034] This embodiment has the following beneficial effects: ① Solve the dust problem at the source: By using a targeted water spray desliming process, the main source of dust (fine coal slime with a particle size ≤0.1mm) is removed from the source, resulting in a significant reduction in dust during the sandblasting process and a significant improvement in the working environment.

[0035] ② High dehydration efficiency and low energy consumption: It adopts a two-stage dehydration mode of "centrifugal dehydration + hot air drying". Centrifugal dehydration first mechanically removes most of the water, which greatly reduces the load on the subsequent hot air drying and has significant economic benefits.

[0036] ③ Excellent product performance: The prepared coal gangue blasting abrasive has uniform particle size, high hardness, and sharp edges, exhibiting excellent cutting ability and rust removal efficiency. Simultaneously, the washing and dehydration processes effectively reduce the content of soluble salts, minimizing the risk of rust re-emergence on the metal surface after blasting.

[0037] ④ Low cost and outstanding environmental benefits: Using waste spiral separator tailings as raw materials, it realizes "turning waste into treasure" with extremely low raw material costs. The entire process can achieve wastewater recycling, with no secondary pollution, making it a green and economical path for solid waste resource utilization.

[0038] Based on the above embodiments, this embodiment also provides a method for preparing coal gangue blasting abrasive, such as... Figure 2 The diagram shown is another flowchart of the preparation method, including: S201: Coal gangue tailings are sent to a hydrocyclone for coal slime removal to obtain coarse-grained coal gangue.

[0039] S202: Centrifugally dewater coarse coal gangue to obtain dewatered coal gangue.

[0040] S203: Dehydrated coal gangue is sent to a hot air drying system for drying to obtain dry coal gangue blasting abrasive.

[0041] In one or more embodiments, the dehydrated coal gangue has a moisture content of 10% to 15%.

[0042] In one or more embodiments, the drying temperature is 80°C to 150°C.

[0043] In one or more embodiments, the moisture content of the coal gangue blasting abrasive is less than or equal to 0.5%.

[0044] In one or more embodiments, the particle size of the coal gangue blasting abrasive is 0.1~2mm, and the Mohs hardness is greater than or equal to 5.

[0045] In one or more embodiments, the underflow inlet of the hydrocyclone is equipped with a high-frequency vibrating screen with a spraying device for removing fine coal slime from the surface of the coal gangue tailings, wherein the particle size of the fine coal slime is less than or equal to 0.1 mm.

[0046] In one or more embodiments, the centrifugal dehydration process is performed in a centrifugal dehydrator, which is a horizontal scraper centrifuge.

[0047] In one or more embodiments, the heat source for the hot air drying system is waste heat from a boiler or steam from a coal gangue power plant.

[0048] According to another aspect of the present disclosure, a coal gangue blasting abrasive is provided, which is prepared by the above-described preparation method.

[0049] According to another aspect of the present disclosure, an apparatus for preparing coal gangue blasting abrasive is provided, which is applied to the preparation method described above.

[0050] The block diagrams of devices, apparatuses, devices, and systems disclosed herein are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0051] Additionally, as used herein, the "or" used in a list of items beginning with "at least one" indicates a separate list, such that a list of, for example, "at least one of A, B, or C" means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Furthermore, the word "exemplary" does not imply that the described example is preferred or better than other examples.

[0052] It should also be noted that in the systems and methods of this disclosure, the components or steps can be decomposed and / or recombined. These decompositions and / or recombinations should be considered as equivalent solutions to this disclosure.

[0053] Various changes, substitutions, and modifications can be made to the technology described herein without departing from the teachings defined by the appended claims. Furthermore, the scope of the claims of this disclosure is not limited to the specific aspects of the processes, machines, manufactures, events, means, methods, and actions described above. Currently existing or later-developed processes, machines, manufactures, events, means, methods, or actions that perform substantially the same function or achieve substantially the same result as the corresponding aspects described herein can be utilized. Therefore, the appended claims include such processes, machines, manufactures, events, means, methods, or actions within their scope.

[0054] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0055] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. A method for preparing a coal gangue blasting abrasive, characterized in that, include: Coal gangue tailings are sent to a hydrocyclone for coal slime removal to obtain coarse-grained coal gangue. The coarse-particle coal gangue is centrifuged and dehydrated to obtain dehydrated coal gangue. The dehydrated coal gangue is fed into a hot air drying system for drying to obtain dry coal gangue blasting abrasive.

2. The method for preparing the coal gangue blasting abrasive as described in claim 1, characterized in that, The dehydrated coal gangue has a moisture content of 10% to 15%.

3. The method for preparing the coal gangue blasting abrasive as described in claim 1, characterized in that, The drying process is carried out at a temperature of 80℃ to 150℃.

4. The method for preparing the coal gangue blasting abrasive as described in claim 1, characterized in that, The moisture content of the coal gangue blasting abrasive is less than or equal to 0.5%.

5. The method for preparing the coal gangue blasting abrasive as described in claim 1, characterized in that, The particle size of the coal gangue blasting abrasive is 0.1~2mm, and the Mohs hardness is greater than or equal to 5.

6. The method for preparing the coal gangue blasting abrasive as described in claim 1, characterized in that, The underflow inlet of the hydrocyclone is equipped with a high-frequency vibrating screen with a spraying device, which is used to remove fine coal slime from the surface of the coal gangue tailings, wherein the particle size of the fine coal slime is less than or equal to 0.1 mm.

7. The method for preparing coal gangue blasting abrasive as described in claim 1, characterized in that, The centrifugal dehydration process is completed in a centrifugal dehydrator, which is a horizontal scraper centrifuge.

8. The method for preparing the coal gangue blasting abrasive as described in claim 1, characterized in that, The heat source for the hot air drying system is waste heat from a boiler or steam from a coal gangue power plant.

9. A coal gangue blasting abrasive, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 8.

10. A device for preparing coal gangue blasting abrasive, characterized in that, Applied to the preparation method according to any one of claims 1 to 8.

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